The present invention relates to a method and an apparatus for lifting printing products off a stack.
From DEC-C-27 32 591 (and the corresponding U.S. Pat. No. 4,127,262) an apparatus for taking apart a stack of printing products of this kind is know, in which the suction head is moved by a drive mechanism along a closed orbit, the shape of which resembles a hypocycloid. At the top reversal point on this movement path the suction head grips a corner of the printing product at the bottom of the stack at a given moment and carries this corner to the next, bottom reversal point. The drive mechanism, which comprises a planetary gear unit connected to a constant-speed drive motor, is intended primarily for moving the suction head along the aforesaid movement path having a determined shape. Although the speed of the suction head varies during its movement along this path, nevertheless the speed variations which occur are dependent on the design of the drive mechanism and therefore on the shape of the movement path.